Wireless telecommunications systems require transmitters and receivers in order to send and receive information over radio frequency signals in a network configuration. These transmitters and receivers may suffer from interference with other transmitters and receivers in and out of the network configuration. Such interference may be caused by each transmitter operating at a different transmitting power level. Control of the transmitting power of the transmitters has only been performed at each transmitter and not from a centralized location. Further, the transmitting power of a transmitter within a wireless telecommunication system has proved to be difficult to control with respect to the transmitting powers of other transmitters in the system. Therefore, it is desirable to obtain improved control of the transmitting power of each transmitter within a wireless telecommunications system.
Also, wireless telecommunications systems require radio links be established between corresponding transmitters and receivers in order to provide wireless communication transmissions. Interference and delays occur in achieving acquisition and establishment of each radio link. It becomes inefficient to acquire and establish a radio link every time a call is to be initiated. Problems with interference also occur if a radio link is maintained whether or not a call is in progress due to power needed to maintain the radio link. Therefore, it is desirable to avoid establishing a radio link for each call and avoid requires a greater amount of circuitry and software support to identify information from a corresponding transmitter operating at a different phase. Additionally, a phase difference between a receiver and transmitter may also be affected by changes in a path delay between the transmitter and the receiver. Therefore, it is desirable to be able to control the phase of transmitters and receivers in a wireless telecommunications system to provide improved radio frequency signal transmission.
Transmitters of the originating or destination sources may send information at one phase and the receivers of the destination or originating sources may receive information out of phase. In such a situation, the receivers will not know know at what portion in the data stream the receive process has started. Information is partitioned into frames and to adequately process the information the beginning of each frame should be identified. Conventional techniques to frame align information are cumbersome, slow in frame identification, and may lose frames of information. Therefore, it is desirable to quickly and easily identify the beginning of each frame of information to achieve proper processing.
WO-A-93/14588 describes a CDMA cellular communication system in which to permit maximum flexibility within a predefined structure, the communication of signals from the mobile station may be characterised in the form of an access channel or a traffic channel communication, in which various combinations of user traffic and/or signalling traffic may be transmitted.
U.S. Pat. No. 5,161,168 discloses a technique for wireless telephone communications between a central terminal and a plurality of subscriber terminals, in which a number of signals associated with the subscriber terminals are spread, the spread signals are combined, and then the combined signal is transmitted.
U.S. Pat. No. 5,103,459 discloses a spread-spectrum telecommunications system whereby the mobile units are synchronised using phase offset information contained in a pilot signal.
U.S. Pat. No. 5,383,219 discloses a CDMA telecommunications system in which a power control bit is multiplexed in place of another bit in the transmission frame prior to transmission of that frame to a mobile unit, the mobile unit then using the power control bit in order to determine whether to increment or decrement its output power level by a predetermined amount.